JP2000138014A - Coaxial cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact coaxial cable that is excellent in plating adhesion and has an excellent high-frequency characteristic. SOLUTION: An insulation 2 made of a fluorine resin on a conductor 1, an ABS resin film layer 3 on the insulation 2, an electrodeless-plated metal layer 4 on the ABS resin film layer 3, an electroplated metal layer 5 on the electrodeless-plated metal layer 4 and a protective covering layer 6 on the outermost layer are formed. For this coaxial cable, the adhesion strength of the plating is enhanced by interposing the ABS resin film layer 3 between the insulation 2 of which surface is modified and the plated layer 4, so that the durability of the plating can be improved. The ABS resin film layer 3 is an extremely thin layer and does not affect a high-frequency characteristic, so that an excellent high-frequency characteristic can be provided. Additionally, because the coaxial cable does not use metal braiding and is composed of the plated metal layers, the fine diameter of the coaxial cable can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial cable used as a signal transmission line for high-frequency components such as measuring equipment, information communication equipment, and information processing equipment requiring particularly excellent high-frequency characteristics.

[0002]

2. Description of the Related Art In recent years, measuring equipment and information communication equipment have been increasingly miniaturized, and consequently, coaxial cables used have also been required to be reduced in diameter. Therefore, instead of the conventional metal braided layer, the surface of the insulator is subjected to surface modification such as chemical treatment so that metal plating is easily attached, and then a metal plating layer or a metal deposition layer is provided on the surface of the insulator. A coaxial cable having a reduced diameter is known (for example, Japanese Utility Model Application Laid-Open No. 62-3311).
7). However, when a low dielectric loss fluororesin having excellent high frequency characteristics is used as the insulator of the coaxial cable as in the above example, the metal layer is hard to adhere and the thickness of the metal layer becomes uneven. In addition, there is a quality problem that the adhesion between the insulator and the metal layer is weak and the durability is poor. Furthermore, in order to improve the adhesion (adhesion) to the insulator and to facilitate the peeling of the end, a resin, which is more easily electrolessly plated than the insulator, is extruded or taped between the insulator and the plating layer. A coaxial cable is also known (for example, see
-272553). However, even in this method, it is difficult to reduce the diameter because the thickness of the insulating layer is thick, and the high-frequency characteristics are not affected because the resin is coated with a resin that has different electrical characteristics from the insulator and is easily electrolessly plated. There is a problem of getting out.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a coaxial cable which is excellent in plating adhesion and compact and has excellent high frequency characteristics. is there.

[0004]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, they have good adhesion to both the modified surface of the insulator and the plating layer, and have an effect on high frequency characteristics. The present invention was completed with the idea of providing an ABS resin coating layer having a small thickness, which does not give the layer, between the insulator and the electroless plating layer.

That is, the present invention relates to a method for extruding and coating a solid or stranded conductor having an outer diameter of 0.03 mm or more with a thickness of 0.03 mm.
An insulator made of a fluororesin having a thickness of 5 mm or more, an ABS resin coating layer having a thickness of 0.05 μm to 3 μm applied on the insulator, and an electroless metal plating layer having a thickness of 0.5 μm to 5 μm on the ABS resin coating layer A thickness of 5 mm on the electroless metal plating layer.
A coaxial cable characterized in that an electrolytic metal plating layer of at least μm is provided and the outermost layer is formed of a protective coating layer.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. In FIG. 1, 1 is a conductor, 2 is an insulator,
3 is an ABS resin coating layer, 4 is an electroless plating layer, 5 is an electrolytic plating layer, and 6 is a protective coating layer. As the conductor 1, a single or stranded conductor such as a silver-plated tin-containing copper alloy wire or a copper-coated steel wire having an outer diameter of 0.03 mm or more is used. Examples of the insulator 2 include: tetrafluoroethylene resin (PTFE), ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer resin (PFA), ethylene tetrafluoride-propylene hexafluoropropylene copolymer resin (FEP), It is made of fluororesin such as fluorinated ethylene-ethylene copolymer resin (ETFE).
Hexafluoropropylene copolymer resin (FEP) is particularly preferred. The thickness of the insulator 2 is 0.035 mm or more. Next, the outer periphery of the insulator 2 is made of metal sodium-naphthalene,
Or a chemical treatment of metal sodium-ammonia system,
Alternatively, the surface is modified by an excimer laser or the like.
Next, an ABS resin coating layer 3 having a film thickness of 1 μm to 3 μm is applied to the outer periphery of the insulator 2 that has been subjected to the above-mentioned surface modification treatment. The coating layer 3 is formed by a method such as dipping or coating in an ABS resin tank dissolved in a solvent.

Here, the ABS resin coating layer 3 is an extremely thin film having a thickness of 0.05 μm to 3 μm, and cuts into the surface of the insulator on which the surface has been modified to form irregularities, and the insulating effect is exerted by the anchor effect. Strong adhesion to the body surface is obtained.
Further, since the ABS resin has good adhesion to the plating in the next step, this AB resin is placed between the surface-modified insulator and the plating layer.
By providing the S resin coating layer, compared to the conventional method,
The plating durability is remarkably improved. Here, since the thickness of the coating layer 3 of the ABS resin is extremely thin, 3 μm or less, excellent high-frequency characteristics can be expected without affecting the high-frequency characteristics at all. Next, the surface of the ABS resin coating layer 3 is subjected to electroless plating. The thickness of the electroless plating layer 4 is 0.5 μm.
A copper plating layer of about 5 μm is provided. Further, an electrolytic plating layer 5 is provided on the outer periphery of the electroless plating layer 4. Electrolytic plating layer 5
Is provided with a copper plating layer having a thickness of 5 μm to 30 μm. As the type of copper plating, there are copper cyanide plating, copper sulfate plating, and the like. In the present invention, copper sulfate having good spreadability and high bending resistance was selected. Finally, a protective coating layer 6 having a thickness of 0.02 mm or more is provided on the outer periphery of the electrolytic plating layer 5. As the protective coating layer 6, various coating materials such as PVC, polyethylene, and polyurethane can be selected.

[0008]

EXAMPLE As the conductor 1, 0.3% of an outer diameter of 0.05 mm was used.
A silver-plated single wire of a tin-containing copper alloy was used. The insulator 2 was formed by extrusion coating a tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) to a thickness of 0.05 mm.
Next, before entering the plating step, the surface and outer periphery of the insulator 2 were surface-modified with a KrF excimer laser having a wavelength of 248 nm. Next, ABS is applied to the outer periphery of the insulator 2 subjected to the surface modification.
The resin was applied at a thickness of 1 μm. Further, the thickness of the electroless plating on the ABS resin coating was 3 μm, and the thickness of the electrolytic plating was 27 μm. Finally, polyethylene was coated and coated as a protective coating layer to a thickness of 0.035 mm. As described above, a small-diameter coaxial cable having an outer diameter of 0.28 mm, which is difficult with a metal braid, can be easily formed. Also, the high frequency characteristics were equivalent to those of the conventional coaxial cable.

[0009]

According to the coaxial cable of the present invention, the ABS resin coating layer is interposed between the surface-modified insulator and the plating layer so that the adhesion of the plating can be increased and the durability of the plating can be improved. Further, the ABS resin coating layer is an extremely thin layer, and does not affect the high-frequency characteristics, so that excellent high-frequency characteristics can be obtained. Furthermore, since the metal braid is not used and is constituted by the metal plating layer, the diameter of the coaxial cable can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a coaxial cable of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor 2 Insulator (fluorine resin) 3 ABS resin coating layer 4 Electroless plating layer 5 Electrolytic plating layer 6 Protective coating layer

Claims (2)

[Claims] 1. An insulator made of a fluororesin having a thickness of 0.035 mm or more, which is extrusion-coated on a single wire or a stranded wire conductor having an outer diameter of 0.03 mm or more, and a film thickness of 0.03 mm applied on the insulator.
An ABS resin coating layer having a thickness of 05 μm to 3 μm, an electroless metal plating layer having a thickness of 0.5 μm to 5 μm on the ABS resin coating layer, and an electrolytic metal plating layer having a thickness of 5 μm or more are provided on the electroless metal plating layer. A coaxial cable, wherein the outermost layer is formed of a protective coating layer. 2. The coaxial cable according to claim 1, wherein the surface of the insulator is surface-treated by excimer laser treatment or chemical treatment.